api.weixin.qq.com unknownHost

在后台调用code换session_key接口时报错，

java.util.concurrent.ExecutionException: java.net.UnknownHostException: api.weixin.qq.com: unknown error

at java.net.Inet4AddressImpl.lookupAllHostAddr(Native Method)

at java.net.InetAddress$2.lookupAllHostAddr(InetAddress.java:928)

at java.net.InetAddress.getAddressesFromNameService(InetAddress.java:1323)

at java.net.InetAddress.getAllByName0(InetAddress.java:1276)

at java.net.InetAddress.getAllByName(InetAddress.java:1192)

at java.net.InetAddress.getAllByName(InetAddress.java:1126)

at org.eclipse.jetty.util.SocketAddressResolver$Async.lambda$resolve$1(SocketAddressResolver.java:167)

at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:671)

at org.eclipse.jetty.util.thread.QueuedThreadPool$2.run(QueuedThreadPool.java:589)

at java.lang.Thread.run(Thread.java:745)

之前一直没有这个问题 想问下这是怎么回事